Method of making purified sirup



May 18, 1943 J, F, WALSH 2,319,649

METHOD OF MAKING PURIFIED SIRUP A Filed Nov. 50, 1940 REF/NED STHRC'H SULFUR/C HUD SUSPE/VJ/ON STHRCH Mfl/(E- UP THNK CONVERTER L/ME.

CU/YGUL/l TED METER/4L8 I F/LT L/GHT LIQUOR DECOLOR/ZER &

LIGHT LIQUOR EVHPO/FflTUR HEfil/Y LIQUOR .DECOLOR/ZER F/NHL EVHPORHTOR V PUR/F/ED SYRUP INVENTOR Jrgws 1'7 Walsh Ag, ATTO RN EY rproteins and fats which; are present;

I metalicompoundszintthe-sirup.. :Econtent; 0 dissolved -tralizing:-is ilimet Patented May 18, 1943 .llam es F. ;Walsh, Yonkers, Y1, airtime [to American Maize lroducts Company, acorpo- I [ration of Maine Application November 30, 1940, Serial Ni. 361,934.

n V 2 Claims.

[This invention relateszto purified sirup and the method of making it; More'particularly, the invention relates to starch conversion sirup oflow ash. :content, minimized tendency: to carameliza- .tionon moderate heating, and; substantially: no

effect upontthe inversion of heated-sucrose 50111-- tions containing. thesiruprel a :Inv making starch conversionaproducts, it is cus-' tomary to suspend starchzin water. containing a 'smallproportionof acid and heat the mixture with steam at superatmospheric pressure untilthe starch; is 'convertedlargely to sugars and dextrines. The resulting solution is then treated with alkali, to increase the pH and cause coagulation ofxcoagulable materials such as certain coagulated, materialsare then separated, as by skimming followed by filtration, and therresultking clarified sirup is refined. The usuallrefining includes-passage of thesirup over decolorizing carbon, vacuum evaporation to. form heavy liquor, decoiorizing the heavy liquor, and then vacuum evaporation of the heavy liquor to the conp-centrationdesired;

gThe -acid used in "effecting. the conversion of starch ordinarilyis'i hydrochloric acid." Thealkalb used, to neutralize .the acid iand yestablishathe pH -aiataaiidesirable va-lueifor'i efiectingtthe coagulation,- vusually;asodiumkcarbonatek i-i-allkalt riunfortunately rincrease the: content. of

Therer'sissi lessrincreaseii-i metal-compoundsv whenttheaci'dgusediinthe con- T version: is ssulf-urica ands-the;alkali @used for neu- I The lime-forms.azprecipitate of calcium? sulfate tWh1Ch'-; removes pa,- considerable part of the sulfuric-acid original! use'diaswelltas ofthe-lime.

. .There is 1eft,.however, aiSOhltlOn-Which.155581711- rated with calcium: sulfate wand which; causes .difllcultyiln-riurther processing oreuse of the sirup Thus, the/calcium sulfate remaining dissolved in the solution fouls [the .de olorizingimaterial used -to reduce the intensity :0, color. of the ,sirup, with consequent lossofi -acthrity of the said material. Also, the Y calciurrrisulfate, :being less soluble in boiling than in coldwat'er; deposits as azhard ,zscale on.evaporator: equipment; panticularly' upon r the? steam .pipesnz -The dep'ositiomof r the calcium 5: ,1 sulfate continues; to etheiend. ofetheyevaporation. n Th calcium sulfate-.appearsz za'lsosas: at-cloud; 01E

suspended:-materialminat-ithe final vconcentrated sirup; filtration,ofatheiviscous concentrated 511 3111) to remove the cloud being so tedious as;,to-';be impracticable Finally, the calcium sulfate left dissolved in' thev finished sirup is objectionable in promoting The.

fcaramelization on heating the" sirup, as, for ex-, ample, to 275 F. or somewhat higher in making hard candy from a. composition including starch conversionsirup-products; Furthermore, the inorganic contentwof thesirup .causes inversionof 1 sucrose in those :operationsin which the sucrose is heated in thepresence of the sirup;

The present invention provides a purified sirup and a convenient method of making it, the sirup being of low ash content and of minimized tendency to caramelization at elevated temperatures ofthe order of 125 F. to 300 F. or so.

Briefly stated, the-invention comprisesconverting starchin'the'presence of acid, separating material coagulable on increasing the pH,-by-the addition of an alkali, and then subjecting the resulting clarified sirup to theaction of a hydrogenbase exchanger andanacid exchanger so as to remove from the siru p most of .themetal content and also the .acidity. In the preferred embodiment, the invention comprises effecting the ,conversion'with" sulfuric acid, subsequently neu- .tralizing with limeto the pH stated later herein,

. and 1 then, treating the sirup with the two v types ,of eXchangers as described, to remove metalland acid. a

'ltzwill be understood that the base exchangers I v10f the kind'used .by me are those whichv.are emplayedconventionally,ior the removal of metals, theg'metals presumably being -substituted :in the solution by hydrogen. The acidexchangers remove acidity without introducing any substantial proport n a considered-,that the acid ianion) exchanger re- For simplicity, it may be 1 I moves ac d -I- t e :siruu;v poss b y. lar e y by substituting hydroxyl groups for acid radicals,

. th radicals -becoming combinedpr adsorbed in he e xcha s rt a 1 A suitable sequenceof steps in m yfprocesstis shownin thefiow sheet of the attached drawing, towhich reference is made.

In aspeciflc, example of the practice-oi the. invvention, the following procedure is used.

starchy material, such as refined starch from 1 potatoes, cornQwheator barley or an impurelmaterial known as table-head starch, is suspended in water. and, conyertdto reducing sugars and trines, by, hydrolysis; in thepre'sence' of an addedacid Thus. thestarchy material may be ixedwith water in such proportion as togive a fffj'qe'risity ot bo t; 12" t v 233 e; Sufiflcient sulfuric ,acidjis added, with stirring, to establish the p l -I atjaboutofi-to 2. Conversion is theneifected solved.

and preferably 4.5 to 6.

under steam pressure, at usual temperatur and in about the usual period of time.

The conversion may be conducted tostage desired, as, for example, to a D. E. of about 30 to 92, the degree of conversion being selected in accordance with the use to which the product is to be put and being controlled by means of the pH, the temperature, and the period of time during which the temperature of conversion is maintained, all in well known manner.

The resulting solution is then treated with lime so as to adjust the pH to that desired i'or'thej coagulation of coagulable organic substances. Ordinarily the pH is adjusted to about 3.5 to 5." The addition of the lime serves, also, to precip-' itate as calcium sulfate a part oi the sulfuric acid present, some of the sulfate remaining dis- The coagulated organic substances are then separated largely-by skimming. The remaining part ofthe coagulated substances and precipitated calcium sulfate are then separated by filtration, a filter aid being used. The filtrate obtained is clarified sirup,-or light liquor.

The clarified sirup isthen treated wan a hydrogen-base exchanger, to remove metals present in the form of soluble compounds. These metals include those present originally in'small proportion in the starchy material and also that part of the calcium added'originally in the form of lime that failed to precipitate as suiate.

These hydrogen-base exchangers are sometimes called hydrogen aeolites or organolites. After having exchanged hydrogen for metals in solutions and having become spent, they are activated by acid.

Among the materials that meet the requirements of the hydrogen-base exchanger and that may be. used to advantage is the activated organic material produced by treatment of coal, lignite, or wood by the process described by Tiger in Transactions of the American Institute of Mechanical Engineers, 60, No.11, 315-325 (1938) This base exchanger has the property or removing various amounts, up to about 7000 grains or somewhat more, of sodium or other metals from solutions passed slowly over the material, for

each cubic foot or the material. It is preferably used under such conditions as to acidity that the solution in contact with the exchanger is acid tophenolphthalein, say of pH- value below 8.3

Another base exchanger thatmay be used to advantage is the product or the-condensation used any of the commercial base exchangersv which remove metals from aqueous-solutions or their salts-and that do not introduce into the sirup treated any substantialamount of interfering water soluble by-products except acid.

The hydrogen-base exchanger selected is'preferably used in granular form and fllledinto a container or tower. The clarified sirup 'to be loweredin metal content is caused to flow slowly through the cation (base) exchanger, at' such a rate that the'time of contact withthe base exchanger is substantial, say 1 to 4' hours or more.

Ii necessary to separate the base exchanger completely from the clarified sirup the eilluent from the container for the base exchanger is filtered.

The sirup, after being contacted with the hydrogen-base exchanger, is then contacted in like manner with a conventional acidv exchanger to "removeacid' and produce a solution of pH not substantially less than 4.5 to 6, the exchanger selected being one that is unobjectionable in subsequent reflning of the product and that does not introduce metal in substantial amount.

The acid exchanger used is a product such as "a synthetic resin which removes anions and more especially acid, either by adsorption or by replacement by 'water. Thus, the action or the acid exchanger may be considered for convenience either as the exchange of hydroxyl groups for the acid radicals in the clarified sirup or direct adsorption or combination with the acid.

" Acid-exchangers that may be used include the following:

. Aromatic amine-aldehyde :resins modified by introducing, before, during, or alter thecondensation, a group that enhances the basicity of the resin. Thus, the resin may be after-alkylated. In general, the acid exchanger of this type may be' one made as described .in British Patent 495,032, issued on November 4, 1938,-to I. G. Farbenindustrie.

Another acid exchanger that may bexused is made as described in British P atent 495,401, is-

sued on November 14, 1938, to I. G. Farbenindustrie Exchangers of this type are made by resin to react wholly or partially, before or after the condensation with aldehyde,with a substance that contains a CN group linked to a'nitrogen atom, as, for example, with dicyanodiamide. Amongv examples of such exchangers are maminobiguanidylbenzene;

1 The selected acid exchanger may be used in any suitable form, as, for example, asgranules if-the exchanger is itselfiflrm. Or, it may be applied as a surfacecoating over a-granular support such as coke, pumice stone, charcoal, or

plied to the selected support.

activatedcarbon. In fact, the acid exchanger may be formed from ingredients separately ap- Thus, there'may be used an acid exchanger of the kind described in British Patent 506,291'issued on May-25, 1939, to The Permutit Co.- Ltd. et al., as, iorexample. the resinous reaction product of heating,-at 10 to 20 pounds. steam pressurefa solution of -m-phenylene diamine hydrochloride with paraformaldehyde! or other source of formaldehyde.

The exchangers, on becoming inactive or spent, are revivified in manner that is customary ror'the particular exchanger used.

After the removal or metals-and acid bycontacting the sirup'with the exchangers as described, the remaining sirup is" then refined by arated, as by filtration.

usual process of treatment, such-asshown on the flow sheet orthe following procedure. Any suspended particles of. exchanger are sep- The sirup is then passed through a light liquor decolorizer, if 'decolorizing. subsequent to the exchangers treatments-is desirable in the us for'which the finished product is intended. The decolorizing may be made in conventional way, as, for example, with activated carbon or bone char. 3 I I The sirup is then concentrated by vacuum evaporation to heavy liquor, of density about 30 B. This heavy liquor is suitably decolorized as above, in'ac cordance with the usual practice for heavy liquor decolorization.

The heavy liquor is then subjected to evaporation in a vacuum evaporator, to concentration desired for sale or further processing of the product, suitably from 40 to B. In one embodiment of the invention, the decolorized heavy liquor may be further processed by spray drying to dried corn sirup solids of not substantially more than 4 per cent water. Heavy liquor of very high conversion may be solidified to to type block or chip sugar, in accordance with usual technique.

The concentrated sirup without solidification or the solidified material may be used in making confectionery products and baked goods, or for other purposes in which a staple, starch conversion product of very low ash content s desirable.

.Whereas corn starch conversion sirup as ordinarily made contains about 0.2 to 0.35 part of ash for parts of solids present, my purified sirup made from the same starchy raw material contains not substantially more than 0.05 part of ash on the same basis. Corresponding improvement is observed in the conversion sirups from other starchy materials.

My. product of low ash content is without substantial etfect on the amount of inversion of sucrose solutions on being heated therewith. This is an important feature, inasmuch as starch conversion sirups are frequently incorporated into sucrose solutions that are heated, as, for instance, during the manufacture of hard candies andpcompounded sirups.

Itwill'be understood that the details given are for the purpose of illustration and that variations within the spirit of the invention are intended to be included within the scope'of the appended claims.

What I claim is: 1. In making a purified starch conversion sirup, the methodwhich comprises converting .starch by warming with a dilute aqueous solution of sulfuric acid constituting the only acid present in substantial proportion, treating the resulting solution with lime in amount to establish the pH at approximately 3.5 to 5 and cause coagulation of coagulable material and precipi- JAMES F WALSH. 

